Under the Covers: A Different Look for the Duvet

I keep coming across photos of bedrooms in which the duvet sits on the top of the bed in a square and doesn't come down the sides at all. Is this a European thing? I love the look of the set up (much tidier looking than a big draped duvet or comforter) but I am just trying to understand the practicality. Don't the sleeper's arms and feet poke out? Or are there additional blankets underneath?

A German friend told me that German duvets (or Federbett) often smaller than their American counterparts; he says the duvet does indeed rest, fluffed up, atop the bed without spilling over the sides. So perhaps these images are in the German bedding style? I know that in some countries (Denmark, for example) it is not uncommon for hotel rooms to have two individual sized duvets atop a double bed (or two singles pushed together). I imagine these single duvets would be rather small or else they would be spilling all over the place!

To be clear on terminology, duvet (essentially a bag filled with down, feathers or other stuffing) is traditionally used as an alternative to quilts, comforters and bedspreads. Unlike these other coverings, duvets have removable washable covers (aka duvet covers). In Europe, duvets are traditionally used without a top sheet because the duvet cover serves the sheet's function. The duvet may simple be draped over the bed or folded up at the foot of the bed.